For under $1000, I would look at aluminum and steel frames. For road bikes, there are a few major price points. $1000 and under, around $2000, and then much over $2000. The $2000 price point will get you an entry level carbon bike with decent components. Or it could get you a good aluminum frame like the CAAD9 with slightly better components. The farther over $2000 that you go, the more you will start to see diminishing performance returns for your dollar. Similarly, the cheaper you go, the wider the jumps in performance for the buck.

There's a lot of debate about how carbon in the rear triangle affects comfort of an aluminum bike. Some companies like to put it in the seat stays. Some in the chain stays. Some say it doesn't help at all if you can just get a nice stiff frame (like the CAAD9). I think that carbon in the rear is less for compliance and more for stiffness. Carbon in the fork is for stiffness and, therefore, smoothness of the ride.

I think that components are really important. If you're going to be hating your bike because shifting or braking is difficult, or if you're going to be annoyed because you tend to drop your chain or have to take it in frequently for derailleur tune ups, then you won't want to ride it. Better components will make your ride less of a hassle. If you're not going to be racing, then you won't necessarily notice that your bike isn't the stiffest or lightest thing out there. Also the wheels at that price point are all going to be about the same--heavy and tough but not helping you a lot in performance. Get the best parts you can afford on a decent frame. Look for new old stock and end of season (now) sales.

Shimano makes some cheap component groups, and their performance really lacks versus the high end stuff. You won't find so much of a performance gap in Campy and definitely not in SRAM. SRAM Rival is some of the best value stuff out there, IMO. Functionally, Campy and SRAM tend to be pretty equivalent throughout the ranks. Weight and bling are the biggest improvements between groups, I think. I'm not sure that Rival comes on $1k bikes, though...I haven't really looked other than for team deal stuff.

Most importantly, make sure you fit the bike. Test ride a lot of bikes.